Many transportation apparatuses are known. Efforts have been made to keep seats of such apparatuses in a horizontal plane in a single direction when travelling with the apparatus. However, the known apparatuses have a number of drawbacks.
For instance, in US2006061179 a vehicle is disclosed that has a chassis and a driver's seat which is fastened thereto. The seat can be set in its inclination with respect to the chassis and with respect to the longitudinal direction of the vehicle. An inclination sensor determines the angular position of the seat surface of the driver's seat with respect to the horizontal plane. An adjusting device is connected to the chassis and to the driver's seat, and a control and regulating device is operatively connected to the inclination sensor and the adjusting device. The driver's seat can be pivoted around a centre by means of the adjusting device in such a manner that its seat surface is situated essentially parallel to the horizontal plane. The pivot center coincides substantially with the mass center of the passenger in the seat. Thus the passenger is pivoted around its mass center, which is energy efficient.
However, the operating range of the vehicle disclosed in US2006061179 is thus rather limited. The compensation of the vehicle disclosed in US2006061179 is focused on downhill forward-aft compensation, e.g. when travelling along a road. Furthermore, as the mass center of the passenger is only pivoted, a common point of balance of the vehicle and the passenger is shifted. Thus, the vehicle may easily roll over when operated beyond the rather limited operating range, which is defined by the common point of balance shifting beyond the wheelbase of the vehicle. Moreover, lateral inclinations of the vehicle are not foreseen to be compensated. This further limits the operating range of the vehicle to travel substantially horizontal planes, like roads. In addition, lateral tilting is experienced as uncomfortable by the passenger and leads to lateral roll over of the vehicle at low lateral inclinations of the topography of approximately 5 degrees from the horizontal.
In DE19821451A1 an adjustment device is disclosed in form of a rail fixed to a vehicle's chassis. The rail has a straight first part extending horizontally in relation to the chassis on its horizontal surface. The second part of the rail is curved and attached to one end of the first part. A seat holder moves along the rail in reaction to a detected sloping position of the vehicle chassis in relation to the horizontal surface. The seat fixed to the holder is constantly aligned in reaction to the vehicle chassis travelling along the horizontal and sloping surfaces. A third, curved part of the rail is attached to the second end of the first part. The second and third parts are positioned at opposite ends of the first part. Thereby a common point of balance of the vehicle and the passenger are kept low and a compensation is made by moving the seat towards the end portions when a horizontally inclined or declined plane is traversed uphill or downhill, respectively.
However, as shown in FIG. 1, the operating range of the vehicle disclosed in DE19821451A1 is limited. For instance, the range of an angle of inclination I of the horizontally inclined plane traversed by the vehicle, is very limited, as the legs of the passenger will touch the surface of the inclined plane and prevent a continued movement of the vehicle, already at low inclination angles.
Moreover, a large translatory movement of the seat leads to long adjustment times. A considerable amount of time and energy is needed for this additional translatory movement. This translatory delay might also be perceived as discomfortable by the passenger. Especially when starting to travel downhill, the passenger will move from the seat's backrest due to the influence of gravity and the passenger will tip forwardly. The passenger will have to seek support, which is not possible for disabled passengers. Passengers restrained to the seat will also experience this forward acting force as discomfortably.
When travelling over terrain with many changes of inclination, a regulation may not be possible due to this translatory delay.
Also, lateral tilting leads to the same negative effects as described above with reference to US2006061179. The seat configuration disclosed in GB1432614 passively responds to inclination by which the supporting vehicle is affected. Thus, the mass moment of inertia of the seat configuration yields a time delay of the response, making the travelling over terrain unpleasant.
The vehicle disclosed in JP04306181, has drawbacks regarding capability in traveling over terrain with many changes of inclination, not only between the front and back wheel, also between the left and right hand-side of the vehicle. The wheelchair disclosed in U.S. Pat. No. 6,325,167 has similar drawbacks regarding oblique inclination in respect to chosen travel direction. Furthermore, the disclosed construction has similar operational drawbacks as discussed above regarding DE19821451A1. The dynamic seat leveling device in U.S. Pat. No. 6,026,920 compensates for inclinations when the vehicle is tilting. However the center of gravity of the vehicle and the seated person do not align in the longitudinal direction of the vehicle raise question regarding the efficiency and accuracy of the control of leveling when the vehicle is travelling on a hill. Moreover, the regulation instrument disclosed in U.S. Pat. No. 6,026,920 yields a digital leveling control as the instrument detects whether the inclination is above a certain predefined angle or not and adjusts accordingly, i.e. no gradual adjustment of the seat leveling is provided.
The leveling disclosed in U.S. Pat. No. 4,647,053 is capable to adjust lateral inclination changes by winding a wire attached to the respectively left and right hand-side proportion of the body of vehicle. A similar controlling instrument is used in U.S. Pat. No. 4,647,053, as above in U.S. Pat. No. 6,026,920, thus the disclosed leveling behavior is similarly disadvantageous.
Another adjustment system for leveling is disclosed in U.S. Pat. No. 3,857,533 using a mechanical arrangement with fingers and a curved rack. However, if absolute leveling is required the fingers and matching notches in the rack must be small, which makes the construction less strong to withstand a heavy payload.
A stabilizing system is disclosed in U.S. Pat. No. 5,207,408 using a pressurized gas cushion. However, the system requires a first and a second structure for keeping the stabilizing effect working. The second structure is positioned within a hollow part of the first structure using shock absorbers and/or actuators. The disclosed construction restrains e.g. a payload plane as the first structure circumference making the vehicle less appropriate for e.g. loading bulky cargo. Another situation could be that a payload plane is elevated above the first structure to accommodate a large enough plane, however this will make the vehicle more instable as the center of gravity is shifted upwards.
Furthermore, another issue is that known vehicles, such as disclosed in DE19821451A1 have an as large wheelbase (distance between wheel axles) as possible, and an as low center of gravity of the payload as possible. However, this implies that the payload is oriented very low, which might be disadvantageous in certain situations. For instance, when a passenger is seated in such a vehicle, the low arrangement of the seat in relation to ground may be disadvantageous. An example is a use in terrain where an overview over the path to be traveled is important to get. Therefore, a more elevated arrangement of the payload carrying surface would be desired as is possible with conventional vehicles, with preserved or improved stability and tilting security. Also, a higher seat position would allow for eye contact of a seated person with standing persons. This is a social issue, and there is a need to provide this capability without impairing versatility of the vehicle with regard to virtual independence of transportation topography.
A further issue with prior art vehicles is high weight, in order to provide stability of the vehicle, in particular with a payload of large weight.
This limits the practical use of such vehicles, e.g. when wanting to travel in an elevator which has limited surface and load capacity available.
Lighter vehicles also need less propelling energy, which is a desired advantage.
Hence, there is a need for an improved transportation apparatus of less weight and/or footprint area, while allowing safe travel along a wide range of inclinations.
In addition, a combined active left-right and simultaneous active forward-aft compensation keeping a horizontal plane of a payload surface is desired.
Moreover, maintaining arbitrary planes of a payload surface of a transportation apparatus, other than a horizontal plane, may be desired.
Thus, there is a need for an improved transportation apparatus or compensation device and method for a payload therefore.
Hence, an improved transportation apparatus or compensation device, system or method therefore would be advantageous and in particular allowing for increased flexibility, range of operation, cost-effectiveness, and/or safety would be advantageous.